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This chapter describes the functions that deal with the text in a
buffer. Most examine, insert, or delete text in the current buffer,
often operating at point or on text adjacent to point. Many are
interactive. All the functions that change the text provide for undoing
the changes (see Undo).

Many text-related functions operate on a region of text defined by two
buffer positions passed in arguments named start and end.
These arguments should be either markers (see Markers) or numeric
character positions (see Positions). The order of these arguments
does not matter; it is all right for start to be the end of the
region and end the beginning. For example, (delete-region 1
10) and (delete-region 10 1) are equivalent. An
args-out-of-range error is signaled if either start or
end is outside the accessible portion of the buffer. In an
interactive call, point and the mark are used for these arguments.

Throughout this chapter, “text” refers to the characters in the
buffer, together with their properties (when relevant). Keep in mind
that point is always between two characters, and the cursor appears on
the character after point.